Utilizzo congiunto di dati SAR e ottici per il monitoraggio di agroecosistemi risicoli in ambiente tropicale: primi risultati in Bangladesh

Timely and accurate information on crop typology and status are required to reduce food insecurity and better manage agriculture productions in developing countries. In this context agricultural monitoring tools are required to predict in advance unfavorable agricultural trends and could represent efficient support tools. This work focus on the exploitation of remote sensed data to monitor paddy rice in tropical Asian countries. In this context, the monsoon cloud contamination and the small and splitted field sizes represents two limit's factors for an exclusive use of low spatial resolution optical data. This research work wanted therefore to test an integrate use of SAR and optical data for: i) mapping rice-growing areas and ii) deriving phenological dynamics for the whole Bangladesh. Analysis of ten years ASAR WS data was conducted for the 2011 rice-growing season, exploiting the complementarity of ASAR-WS SAR and MODIS optical data. Ten years analysis of ASAR-WS analysis allowed to produce a "Multi-year rice extent map" of rice cropped areas, at one hectare of spatial resolution, while the high temporal resolution of MODIS were exploits to analyze temporal series of spectral indices to detect rice seasons and the occurrence of two phenological events: transplanting/emergence and flowering/heading. The resulting thematic maps, were in full agreement with the local agronomical calendars. Results confirm that a combined use of heterogeneous remote sensed data could provide reliable information for the tropical countries crop productions. Furthermore, these information layers could be provided in a spatially distributed and operative way for every analyzed year.